Rerefined oil or hydrofinished neutral oil for blending superpave asphalts with low temperature properties

ABSTRACT

Mineral lubricant base oils (e.g., neutral oils) can be added to asphalt composition to improve low temperature properties at low addition rates (e.g., oil 1-5%). Rerefined oils (boiling above about 177° C. (350° F.)) have the same properties as virgin mineral lubricant base oils, but most rerefined oils are too dark in color to be used as lube oil base stocks. Their use in asphalt would be ideal as color is not a problem and they are much cheaper in cost than virgin base oils. This can permit disposing of rerefined motor oil. The resulting asphalt compositions exhibit important improvements in low temperature properties, resistance to thermal cracking and expanded useful temperature range.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application relates to, and is useful with co-pending U.S.Pat. No. 5,601,697, filed Aug. 4, 1994.

BACKGROUND OF THE INVENTION

I. Field of the Invention

The invention relates to asphalt compositions and to process for theimprovement of their properties. The invention further relates tomodified asphalt compositions useful in a variety of applications,particularly paving asphalts, and to construction methods utilizing suchcompositions.

II. Description of the Prior Art

Asphalt based materials are used extensively in a wide variety ofapplications. For example, asphaltic material is widely employed as aprimary ingredient in coating compositions for structures, in sealants,and in waterproofing agents. Asphalt compositions have been used inpaving mixtures with considerable advantage for many years. Manymanufactured roofing materials, such as roofing shingles, impregnatedfelts, tars, mastics, and cements are also based on asphalt andcompositions thereof.

U.S. Pat. No. 3,930,988 to Johnson (Phillips) teaches the process fortreating used motor oils for reduction in ash content and metals.Further treatment by filtration through absorbents and thenhydrotreating renders an oil product suitable for reuse in lubricatingstocks. This patent provides a process for preparing lubricatingmaterials which may be suitable for use in the present invention butdoes not teach the significance of using lubricating stocks with asphaltfor improvement in low temperature performance properties.

U.S. Pat. No. 4,250,021 to Salusinszky teaches a process for removingmetals and water from used lubricating oils rendering a product suitablefor refinery feedstocks, fuel oil, or as blend stock for otherhydrocarbon products or as rerefining feedstock. The claims of theinvention deal strictly with the process of treating used oil materialsand the ingredients used therein. No mention is made relative to thepresent invention which finds particular advantage in using apredominately paraffinic lube stock as a diluent/plasticizer forenhancing the low temperature properties of asphalt paving compositions.

U.S. Pat. No. 4,381,992 to Wood et al. (Phillips) teaches the processfor purification of used oil by removal of the ash forming componentsand then subjecting the material to vacuum fractionation. The patentdiscusses that such fractionation renders a bottoms material while tooheavy for use as a lubricating oils, could be use as a gear oil or as anasphalt additive. No further mention of usefulness of the bottomsmaterial is made. The claims of the invention deal only with thepurification of used oil processes, a method for fractionating the sameand in no form discuss the novel findings of our invention.

U.S. Pat. No. 5,098,556 to Go et al. (Lyondell) teaches the purificationof white oils to remove color producing bodies detrimental to the acidtreating process. The invention teaches the process for passing whiteoils through acid treated clay filtration to remove RCS (readilycarbonizable substances) which render the oils undesirable for use. Itdoes not teach the use of oils for improving low temperature performanceof paving grade asphalts which is the novel claims of the presentinvention. The oils produced by this invention could be used in ourpresent invention as alternatives to the specified hydrofinished neutraloils. However, their cost from the purification process would renderthem unattractive for use in asphalt.

U.S. Pat. No. 3,455,716 to Loring et al. (Sinclair) teaches theproduction of film forming coating compositions providing corrosioninhibiting properties. No mention is made in the invention of theusefulness in asphalt paving compositions for improvement of lowtemperature performance.

U.S. Pat. No. 2,970,099 to Illman (Shell) teaches the alkylation ofasphaltenes for the improvement of weathering, viscosity-temperatureslope, and sweating tendencies of asphalt compositions. The inventionfurther comprises oxidation or air blowing of the asphalts inconjunction with alkylation. Further it teaches the use of 25 to 75parts by weight of a mineral lubricating oil, well outside the range ofusage within our invention, with the alkylated asphaltenes for use asroofing asphalts. Our present invention does not require alkylation,however the use of asphalts produced by the process of this inventionmay be used within our invention as the base asphalt. Illman does notteach the use of hydrofinished neutral oils for improvement of lowtemperature properties of paving asphalts.

U.S. Pat. No. 2,947,697 to Vierk et al. (Sinclair) teaches theproduction of protective wire rope lubricants comprising oil,polyethylene and oxidized asphalt. It does not teach the findings of thepresent invention for paving asphalts.

U.S. Pat. No. 2,870,080 to Illman et al. (Shell) teaches the productionof an oil asphalt plastisol comprising a continuous oil phase in which apulverized asphalt is suspended. Said composition of this invention isnot homogeneous nor continuous until heated and fused at temperaturesabove the softening point of the asphalt component. Said asphalts inthis invention will have 0-5 penetration and softening points of 82-116°C. (180-240° F.). The invention teaches the production of said asphaltsby severely high steam distillation or solvent precipitation and saidasphalts then being ground to a fine particle size and suspended in anoil carrier to form a plastisol with lower processing and handlingviscosities until fused back into a continuous phase. The invention doesnot teach the novel findings of our present invention for producing lowtemperature grades of Superpave asphalts.

U.S. Pat. No. 5,397,459 to Butler (Exxon) teaches the low severityhydrotreating of used lube stocks which contain only low levels ofadditives such as industrial circulating oils. Such oils are required inlow severity lubricating applications to produce lubricating basestockoils. This invention could produce oils suitable for use in our presentinvention. It does not teach the use of said oils with asphalts for lowtemperature performance improvements.

III. Problems Presented by Prior Art

Regardless of the particular manner of formation or application of theparticular asphalt mixture, durability is an important matter in thecase of most asphaltic materials. For instance, in the case of a pavingasphalt composition, durability of the road surface is a primaryconcern. The degree and rate of hardening of the paving asphaltcomposition or cement during application and while in service (so-called"age hardening"), caused by an increase in viscosity of the asphaltmixture and gradual loss of flexibility, are factors affecting thedurability of an applied surface. At least one worker in the art (i.e.,Januschke, Industrial Engineering Chemistry Product Research andDevelopment, Vol. 10, 1971, 209-213) has concluded that the reaction ofthe asphalt composition with atmospheric oxygen is the principal causeof asphalt hardening in pavement. Accordingly, the retardation of agehardening has been the object of extensive study.

Conventional refined asphalts have been found through the implementationof the Strategic Highway Research Program(SHRP), now Superpave binderimplementation to be incapable of meeting requirements for resistance tolow temperature thermal cracking in certain climatic areas orconditions. Modification using various types of modifiers such asplastomers, elastomers, chemical gellants, and chemical modifiers do notfully satisfy the improvement in both high temperature ruttingresistance and improved low temperature cracking resistance.

Conventional practice has been to add softer asphaltic compounds oraromatic oils or other additives to soften or plasticize the asphaltcomposition. In order to reach acceptable low temperature properties,excessive amounts of soft asphaltic materials or fluxes must be added.In addition, aromatic oils are normally required in such amounts thatwhen used in combination with polymers can, through the action of theincreased aromaticity from the oil, cause the level of polymer requiredto reach the desired level of rutting resistance to become undesirablefrom excessive cost rendering the composition not feasible for use as apaving composition.

As a result of the 1987 Intermodal Surface Transportation Efficiency Act(ISTEA), a $150 million research study was commissioned in which $50million was spent towards asphalt research for improving asphaltpavements. As a product of that research which was concluded in 1992,the Strategic Highway Research Program(SHRP) produced what is now knownas the Superpave Performance Graded Binder Specification in whichasphaltic binders are graded or characterized according to theirrelative performance in resistance to rutting, shoving or deformation athigh temperatures, fatigue at intermediate temperatures, and thermalcracking resistance at low temperatures. Asphalts which normally wouldbe graded either under the penetration or viscosity specifications willnow be graded as PG or Performance Graded binders. As such, theirdesignation will be representative of their resistance at both high andlow temperature, indicating their useful temperature range as a PG AA-BBwhere AA=high temperature resistance in degrees Celsius and BB is lowtemperature cracking resistance in minus degrees Celsius, i.e., PG 64-22would prevent rutting up to 64° C. (147° F.) and low temperaturecracking to a minus 22° C. (72° F.). Areas of high loading or slow orstanding traffic as well as areas where temperature extremes can beexperienced in excess of 86° C. (187° F.) between high and lowtemperature levels will require the use of modifiers to obtain theincreased useful temperature range. As a result, it has been common toadd or start with softer asphalts to reach low temperature propertieswhile adding modifiers such as polymers to achieve high temperaturerutting resistance. The use of aromatic oils has been included to alsogive low temperature properties. As such, extensive levels of polymeraddition is required to regain high temperature properties, especiallywhen using aromatic oils as their use tends to solvate the polymer to ahigher degree and thus require a higher level of polymer to be used toobtain the desired property.

Notwithstanding the considerable previous efforts expended to provideasphalt compositions having improved low temperature crackingresistance, and to provide a method of improving asphalt durability,there has remained a continuing need, particularly with paving asphalts,for improved compositions and methods. The invention addresses thisneed.

SUMMARY OF THE INVENTION

I. General Statement of the Invention

According to the invention, addition to asphalt compositions of minerallubricant base oils (MLBO) preferably hydrofinished (HF) neutral oils,more preferably 100-325 neutral oil, gives a distinct improvement in lowtemperature properties at low addition rates. Rerefined oils (boilingabove about 175° C. (350° F.)) have the same properties as the 325hydrofinished (HF) virgin base oil. Most rerefined oils are too dark incolor to be used as lube oil base stocks but their use in asphalt wouldbe ideal as color is not a problem and they are much cheaper in costthan virgin base oils, such as 325 HF. This also provides a new means todispose of rerefined motor oil made by solvent extraction, distillation,etc., of used motor oil. This material is also suitable for blendingwith solvent deasphalting (SDA) bottoms as an alternative to thearomatic extract and it may not require as much of either 100-325 HF oilor rerefined oil to get the required reduction in viscosity.

Accordingly, in one embodiment, the invention relates to a novelmodified asphalt composition containing, a low temperature crackinhibiting level or stabilizing amount of, a mineral oil lubricantbasestock obtained from the conventional refining of crude petroleum,with or without modification additives such as polymers, chemicalgellants, antioxidants, and to compositions containing such modifiedasphalts. Generally, the modified asphalt compositions will comprise (a)about 0.1 to about 50% of a mineral lubricating oil basestock, and (b)about 0 to about 20% of a polymer modifier, and (c) about 0 to about 5%of a chemical gellant and (d) about 50 to about 99% of an asphaltobtained from conventional vacuum distillation, solvent refining, ornaturally occurring mineral sources, e.g., Trinidad Lake asphalt.Asphalt paving compositions of such exhibit a distinct improvement inlow temperature properties, in their resistance to thermal cracking andfatigue as defined by the use of the new Superpave Performance Graded(PG) Asphalt Binder Specifications. AASHTO MP1. Mineral oil lubricantbase stocks can be added at considerably lower levels to obtain thedesired properties in comparison to addition levels required with fluxes(soft vacuum distillation residues) or aromatic oils. MLBO use alsoimproves and reduces the requirement level for polymers to provide hightemperature performance capabilities. When used in conjunction with airblown asphalts, MLBOs also improve low temperature performanceproperties without excessive sacrifice of high temperature PG gradeperformance, e.g., ruffing resistance.

FEEDS

Asphalts:

Asphalts for use in the present invention are not narrowly critical andcan be any available asphalts. A typical paving asphalt mixturecomprises a mixture of components, principal ingredients of the pavingasphalt mixture being an asphalt composition or cement and aggregate oraggregate material. In such mixtures, the ratio of asphalt compositionto aggregate material varies, for example, according to the aggregatematerial type and the nature of the asphalt composition. As used herein,the terms "asphalt composition", "asphalt cement" or "asphalt binder"are understood to refer to any of a variety of organic materials, solidor semi-solid at room temperature, which gradually liquify when heated,and in which the predominate constituents are naturally occurringbitumens, e.g., Trinidad Lake, or residues commonly obtained inpetroleum, synthetic petroleum, or shale oil refining, or from coal taror the like. For example, vacuum tower bottoms produced during therefining of conventional or synthetic petroleum oils is a common residuematerial useful as asphalt composition. A "paving asphalt composition","paving asphalt cement", or "paving asphalt binder", accordingly is anasphalt composition or asphalt cement having characteristics whichdispose the composition to use as a paving material, as contrasted, forexample, with an asphalt composition suited for use as a roofingmaterial. "Roofing asphalts", for example, usually have a highersoftening point, and are thus more resistant to flow from heat on roofs,the higher softening point generally being imparted by air blowingprocesses by which they are commonly produced. Paving asphalt mixturesmay be formed and applied in a variety of ways, as well understood bythose skilled in the art. For example, the paving asphalt compositionand the aggregate can be mixed and applied at elevated temperatures atthe fluid state of the paving asphalt composition to form the pavementor road surface. See particularly U.S. Pat. No. 5,580,376 to Hayner.

Mineral Lubricating Oils:

The manufacture of mineral lubricant base oils consists of five basicsteps: 1) distillation, 2) deasphalting to prepare the feedstocks, plusoptionally 3) solvent or hydrogen refining to improve viscosity index(VI), 4) solvent or catalytic dewaxing to remove wax and improve the lowtemperature properties, and/or 5) clay or hydrogen finishing to improvethe color, stability and quality of the base oil stocks. Many processesare available to prepare mineral lubricant oils are known to thoseskilled in the art and may be employed in the present invention.

Rerefining of used lubricant base stocks can and may include all or inpart of the above processes utilized to prepare virgin lubricant baseoils. The processes usually provide a blend of light overheadcomponents, lubricant oils, and a residue bottoms material. Severalprocesses commonly known to those skilled in the art may be utilized toprepare compositions useful in the present invention. See particularlycompositions described in the patents listed under prior art, above.

Polymer Modifiers:

The polymers used for modifying asphalts are well-known to those skilledin the art and comprise: Styrene Butadiene (SB), diblock polymers,Styrene-Butadiene-Styrene (SBS), triblock polymers which may be eitherlinear or radial, styrene-isoprene-styrene (SIS), diblocked polymers,hydrotreated SBS, Styrene Ethylene Butadiene Styrene polymers (SEBS),Styrene Butadiene Rubber (SBR), polyacrylamide, e.g., those described inU.S. Pat. No. 4,393,155 to Garrett; Glycidyl-containing ethylenecopolymers in U.S. Pat. No. 5,331,028; or Crumb Rubbers.

Gellants:

Similarly, the gellants are not narrowly critical and can include:chemical gellants such as metallic soaps formed by the neutralization offatty acids and/or rosin acids; organoclays, e.g., bentonites, kaolinclays, etc.; hydrogenated castor oils; oligomers; siloxanes; or otherswell-known to those skilled in the art or included in the patent orother literature.

Antioxidants:

Though not narrowly critical, preferred antioxidants are an oxidationinhibiting or stabilizing amount of a composition selected from metalhydrocarbyl dithiophosphates, and mixtures thereof, and a compositionselected from antioxidant butylated phenols, and mixtures thereof, in aspecified ratio to each other, as described more fully hereinafter.Preferably, the components are added so that the asphalt compositioncomprises from about 0.1% to about 5.0% of a composition selected frommetal hydrocarbyldithiophosphates, and mixtures thereof, and from about0.1% to about 5.0% of a composition selected from antioxidant butylatedphenols, and mixtures thereof, in a specified ratio to each other, asdescribed more fully hereinafier. Most preferably, metal hydrocarbyldithiophosphate component employed is a mixture of suchdithiophosphates, and the metal hydrocarbyl dithiophosphate component issupplied in an amount of from about 0.1% to about 2.0%. The antioxidantbutylated phenol is preferably supplied in a range of from about 0.1% toabout 2.0%. In yet a third and most preferred embodiment, the inventionrelates to a novel oxidation resistant asphalt pavement or compositioncomprising an aggregate or aggregate material and from about 1.0% toabout 10.0% of the novel modified asphalt composition described herein.

Hydrocarbon Solvents:

The hydrocarbon solvents can be any which are capable of reducing theviscosity of the asphalt. Preferred solvents include: mineral spirits;naphthas; kerosenes; and fuel oils.

Emulsifiers:

The emulsifiers include anionic or cationic or nonionic emulsifiers.Those particularly preferred are those described in U.S. Pat. No.4,393,155 to Garrett (6162AUS).

Temperature:

While not narrowly critical, sufficient heat is necessary to maintainthe asphalt composition in the molten state, sufficiently fluid to allowproper mixing and pumpability.

Pressure:

Pressure is optional and atmospheric pressure will be preferred.

Batch or Continuous:

While the invention will most commonly be practiced as a batch process,continuous processing with continuous mixing of the ingredients, e.g.,fed directly into transport trucks, can be utilized.

COMPOSITIONS

In one embodiment, the invention relates to a novel modified asphaltcomposition containing a low temperature cracking and intermediatetemperature fatigue improvement additive of (a) a composition selectedfrom virgin or rerefined mineral lubricating oil base stocks, (b) anelastomeric and/or plastomeric polymer modifier composition andcombinations thereof, (c) a chemical gellant, (a), (b), and (c) beingall or in part present in the composition containing such modifiedasphalts. Generally, the modified asphalt compositions of the inventioncomprise (a) from about 0.1 to about 50% of a composition selected fromvirgin or rerefined mineral lubricating oil base stocks and mixturesthereof, and from about 0.0 to about 25% of a composition selected fromelastomeric and/or plastomeric polymer modifiers and combinationsthereof, and (c) from about 0.0 to about 10% of a chemical gellantselected from metallic soaps formed from the neutralization of fatty androsin acids, organoclays, bentonite clays, hydrogenated castor oils,oligomers, siloxanes, or others well known to those experienced in theart. Unless indicated otherwise, all compositions percentages givenherein are by weight, based upon the total weight of the composition. Asindicated, the virgin or rerefined mineral lubricating oil basestock maybe present as a mixture of such compositions where more than oneviscosity, pour point, or viscosity index(VI) are present. The virgin orrerefined mineral lubricating oil base stocks are preferably present inan amount from about 0.1% to about 30%. The elastomeric and/orplastomeric polymer modifiers and combinations thereof are preferablypresent in an amount from about 0.0 to about 20%. The chemical gellantis more preferably present in an amount from about 0.0 to about 7%. Allpercents herein are by weight of total composition.

PROCESSES

The invention, in a second embodiment, relates to a process or method ofimproving the low temperature cracking and intermediate temperaturefatigue resistance of an asphalt composition comprising blending withsaid asphalt composition, at a temperature sufficient to liquefy saidasphalt composition, a virgin or rerefined mineral lubricating oilbasestock or mixtures thereof, an elastomeric and/or plastomeric polymermodifier or combinations thereof, a chemical gellant(s) in a specifiedratio to each other, as described more fully hereinafter. Preferably,the components are added so that the asphalt composition comprises fromabout 0.1 to about 50% of a composition selected from virgin orrerefined mineral lubricating oil base stocks or mixtures thereof, fromabout 0.0 to about 25% of an elastomeric and/or plastomeric polymermodifier and mixtures thereof, and from about 0.0 to about 10% of achemical gellant in a specified ratio to each other as described morefully hereinafter. Most preferably, the virgin or rerefined minerallubricating oil basestock component employed is supplied in an amountfrom about 0.1 to about 25%, the elastomeric and/or plastomeric polymermodifier and mixtures thereof are supplied in an amount from about 0.0to about 20%, and the chemical gellant and mixtures thereof are suppliedin an amount from about 0.0 to about 7%. All percentages are percent byweight of the total composition.

Asphalt Emulsions:

In a third and more preferred embodiment, the invention relates to anovel low temperature cracking and intermediate temperature fatigueresistant asphalt emulsion composition comprising a virgin or rerefinedmineral lubricating oil basestock or mixtures thereof in an amount fromabout 0.1 to about 25%, a elastomeric and/or plastomeric polymermodifier in an amount from about 0.0 to about 25%, and 0.1 to about 10%of an emulsifier consisting of anionic, cationic or nonioniccompositions commonly known to those skilled in the art, and water inamount from about 1.0 to about 90%. Preferred combination of theemulsion ingredients chosen to produce rapid set(RS), medium set (MS) orslow set(SS) as well as high float (HF ) versions according toparticular agency specifications under which they are to be supplied.

Asphalt Pavement:

In a fourth and most preferred embodiment, the invention relates to anovel low temperature cracking and intermediate temperature fatigueresistant asphalt pavement or composition comprising an aggregate oraggregate material and from about 1.0% to about 10.0% of the novelmodified asphalt composition described herein.

In more particular embodiments, the invention is directed to specificmethods of applications and compositions therefor, such as a novel roofcompositions, crack sealants, coatings, moisture proofing agents andsound deadners.

II. Utility of the Invention

More particularly, the invention relates to novel modified asphaltcompositions characterized by improved low temperature performanceproperties and resistance to thermal cracking, expanded usefultemperature interval range, and to a process for producing such novelasphalt compositions.

DETAILED DESCRIPTION OF THE INVENTION

Any suitable asphalt composition or cement may be employed for producingthe modified asphalt compositions of the invention. For example,industrial asphalts used for coatings, sealants, roofing materials,adhesives, and other applications may be used. Paving grade asphaltcompositions, however, are employed in the preferred embodiment of theinvention. Asphalt compositions may be derived, as indicated, from anywell known bituminous or asphaltic substance obtained from naturalsources or derived from a number of sources such as petroleum, shaleoil, coal tar, and the like, as well as mixtures of two or more of suchmaterials. Typical of such asphalts are the straight run asphaltsderived from the atmospheric, steam and/or vacuum distillation of crudeoils, or those asphalts derived from solvent precipitation treatments ofraw lubricating oils and their fractions. Also included are the thermalor "cracked" asphalts which are separated as cracker bottom residuesfrom refinery cracking operations and the asphalts produced asbyproducts in hydro refining operations. A preferred asphalt is thevacuum tower bottoms that is produced during the refining of syntheticor petroleum oils. The asphalt may be treated or modified before use inthe invention; so called "blown" or "oxidized" asphalts are preferred inroofing asphalt compositions but may be employed for paving applicationswhen modified according to the invention. As indicated, for pavingapplications, any suitable paving grade asphalt may be employed for thecompositions of the invention. Such paving grade asphalt compositionsare often referred to as viscosity, penetration graded, or performancegraded (PG) asphalts having penetrations up to 400 as measured by ASTMmethod D5. Preferred asphalts are the performance graded asphalts suchas PG 46-40, PG 46-34, PG 46-28, PG 52-40, PG 52-34, PG 52-28, PG 52-22,PG 58-40, PG 58-34, PG 58-28, PG 58-22, PG 64-40, PG 64-34, PG 64-28, PG64-22, PG 70-40, PG 70-34, PG 70-28, PG 70-22, PG 76-40, PG 76-34, PG76-28, PG 76-22, PG 82-34, PG 82-28, or PG 82-22. The PG in the titlereferring to Performance Graded, the first numeric designation referringto the binders high temperature rutting or deformation resistancetemperature range limit, and the last numeric designation referring tothe binders low temperature thermal cracking resistance temperaturelimit. Complete specification requirements are outlined inspecifications under AASHTO MP-1-93 Performance Graded Asphalt BinderSpecification. AASHTO is the designation for the American Association ofState and Highway Transportation Officials.

The virgin or rerefined mineral lubricating oil base stocks employed inthe invention are known to be selected from solvent neutral oils, brightstocks, cylinder oils, and naphthene pale oils. (reference paperpublished in ACS Preprints volume 37, no. 4, Aug. 1992 "An Overview ofLube Base Oil Processing", Avilino Sequeira, Texaco Inc. R&D) solventneutral oils (SNO's) are vacuum distilled paraffinic base oils that arerefined for VI appreciation and aromatics removal. They are also dewaxedfor pour point reduction and hydrogenated for stability. These base oilsare characterized by high API gravity, flash point, aniline point, andVI. Bright stocks and cylinder oils are residual base oils manufacturedfrom paraffinic and naphthenic vacuum residua. Bright stocks can bemanufactured utilizing propane deasphalting, solvent extraction orhydrogenation, and solvent or catalytic dewaxing. Cylinder oils aremanufactured using propane deasphalting with solvent dewaxing sometimesutilized to improve pour point. Naphthenic pale oils are vacuumdistilled naphthenic base oils that are refined for aromatics removaland dewaxing is generally not required. Rerefined oils may be obtainedfrom any of numerous processes which are not narrowly critical for thisapplications. Bottoms from the rerefining process can be employed forthe invention but are not desirable due to their potential to containhazardous levels of lead, arsenic, chromium, or cadmium, halogens, andpolynuclear aromatic compounds. Further, lubricant additives such asdispersants, detergents and the like are retained in the bottomsmaterial and can interfere with the efficiency of polymers, gellants, oremulsifiers.

Elastomeric or Plastomeric polymer modifiers or mixtures thereof may beemployed. As used herein, the term "elastomeric" refers to a compositionor compound which is a member of the class of polymers known as blockcopolymers. They can be chosen from either diblock, i.e., StyreneButadiene(SB), or triblock, i.e., Styrene Butadiene Styrene(SBS),Styrene Isoprene Styrene(SIS), Styrene Polyethylene Styrene(SEBS), orrandom block copolymers such as SBR latexes or natural rubberlatexes(neoprene). Recycled Crumb Rubber elastomers may also beutilized. As used herein, the term "Plastomeric" refers to thosepolymers normally chosen from either polymers or copolymers which tendto stiffen a mixture but do not offer an elastic or elastomeric benefit.Such modifiers are normally chosen from polyethylene, oxidizedpolyethylenes, ethylene vinyl acetate, ethylene terpolymers, and otherscommonly available under the trade names Elvax, Elvaloy, Polybuilt,Vestoplast, as well as many others commonly known to those skilled inthe art. The composition of the invention may contain either or both ofthe polymer modifiers to tailor high temperature rutting and fatigueresistance to a specific grade requirement.

Chemical gellants may be used if desired and are normally chosen fromcompositions comprising soaps of resin and fatty acid mixtures asoutlined in U.S. Pat. No. 4,874,432 to Kriech et al., assigned toAsphalt Materials or as outlined in recent patents (U.S. Pat. No.5,437,717; U.S. Pat. No. 5,476,542; and U.S. Pat. No. 5,496,400) toDoyle et al., which concern improvements to that of Kriech, and U.S.Pat. No. 5,221,703 to Ostermeyer et al. Further, common gellants such asstearates and metallic soaps commonly used in the grease-makingprocesses as well as the use of bentonite clays or amine treated ororganoclays may be used for the present invention to control hightemperature grading performance.

Table A summarizes preferred, more preferred and most preferredparameters of the process of the invention.

                  TABLE A    ______________________________________    PROCESS                               More     Most    Parameter             Units   Preferred Preferred                                        Preferred    ______________________________________    Ingredients      Asphalt   Asphalt  Asphalt                     Oils      Oil      Oil                     Polymer   Polymer                     Others    Mixing Order     Asphalt   Asphalt  Asphalt                     Oil       Oil      Oil                     Polymer   Polymer  Polymer                               Emulsifier, etc.                                        Gel, antioxid.                               Water    Water    Mixing Shear             --      Medium    Med.-high                                        High with                                        polymer add.    Temp     ° F.                     100-400   150-390  250-375             ° C.                     35-205    65-200   120-195    Pressure         Optional  Optional Optional    Batch,   --      Batch,    Batch,   Batch,    Continuous       Continuous                               Continuous                                        Continuous    ______________________________________

Table B summarizes preferred, more preferred and most preferredparameters of the composition of the invention.

                                      TABLE B    __________________________________________________________________________    COMPOSITIONS                               More    Most    Elements    Units                    Preferred  Preferred                                       Preferred    __________________________________________________________________________    Asphalts    wt. %                    50-99      70-99   80-99                Type                    refined,   refined or                                       vac. distill.                    natural & reconstituted                               reconstituted                    oxidized    Min. Oil Lub. Base Stock                wt. %                    0.1-20     0.5-15  1-10                Type                    waste oils,                               solv. neutral or                                       solv. neutral or                    solv. neutrals,                               rerefined, arom.                                       rerefined lube                    rerefined, or arom.                               extract base stocks                    extracts    Polymers    wt. %                    0-20       0.5-15  1-6                Type                    PE, EVA, Oxidized                               SB, SBS, SBR                                       SB, SBS                    PF, SB, SBS, SIS,                               SIS                    SBR, SEBS,                    acrylamides    Gellants    wt. %                    0-10       0.5-8   0.5-6                Type                    stearates, tall oil                               stearates, tall                                       metal stearates no                    soaps, clays, ligomers                               oil soaps, clays,                                       soap of tall oil                               organo  fatty acid    Antioxidants                wt. %                    0-10       0.1-5   0.2-3                Type                    butylated phenols,                               butylated                                       butylated                    amines, nickelates, etc.                               phenols phenols/metal                                       hydrocarbyl-                                       dithiophosphate    Solvent     wt. %                    0-90       0.5-50  1-20                Type                    organic solvent                               nonchlorinated                                       diesel, #2 fuel oil,                               organic solv.                                       kerosene,                                       naphthas    Emulsifiers wt. %                    0-20       0.1-10  0.2-5                Type                    clay, anionic, cationic,                               anionic,                                       anionic, cationic                    nonionic   cationic,                               nonionic    Water       wt. %                    0-80       0.5-50  1-30    __________________________________________________________________________

Table C summarizes preferred, more preferred and most preferredparameters of the apparatus of the invention.

                  TABLE C    ______________________________________    APPARATUS    Parameter            Units  Preferred More Preferred                                       Most Preferred    ______________________________________    Vessel     Kettle    Tank        Tank with in-line                                     high shear mixer    Mixer      Stirrer   High shear mixer                                     In-line static                                     mixer or in-line                                     blender    Circulation               Mixer only            Circulating pump                                     with tank mixer    ______________________________________

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plot of AC-5 viscosity graded asphalt cement/oil modifiershowing Examples 12-15 without polymer and with linear SBS polymerversus "pass temperature" (the minimum degrees C at which theformulation passes the thermal cracking test (M value and stiffness) and(upper end of bar) the maximum degrees C at which the formulation passesthe rutting test). The "PG" ratings in Table 1 show the usefultemperature range for each of the formulations in degrees C, e.g.,58.5-35.6 means the formulation can be used from 58.5° C. down to -35.6°C. pavement temperature.

FIG. 2 is a plot of air-blown PG 70 performance graded asphaltbinder/oil modifier showing results of Examples 3-5, 16 and 17 and theirrespective low temperature grading.

FIG. 3 shows a simple kettle 10 mixer 12 to which the ingredients areadded and mixed together to form the finished asphalt composition.

FIG. 4 shows a preferred mixing setup utilizing two separate tanks 20and 22 which receive asphalt and oil, respectively. Tank 20 can alsoreceive the optional polymer and tank 22 can also receive the optionalantioxidant, gellants, solvents, etc. Each tank is equipped withhigh-shear mixers 24-26. The tanks are mounted on load-cells 28 and 29which record the amount of each ingredients added and the contents maybe circulated through a high-shear mill 30 which ensures high dispersedpolymers and other ingredients and produces highly stable emulsions.

FIG. 5 shows a continuous production system in which sources of asphalt(AC) oil and other ingredients are fed to a static mixer 40 whichproduces the finished asphalt product continuously.

DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE 1

Referring to FIG. 4, to a conventional mixing kettle 10 equipped withagitators and circulation to a high shear mill 30 are added in order:93.5 parts by weight of AC5 asphalt cement manufactured to comply withAASHTO Table 2 specifications for viscosity graded asphalt cements, 3.5parts by weight of a styrene butadiene styrene linear triblock polymercomposition manufactured by Shell Chemical Company and marketed underthe Kraton® D-1101 brand name. Polymer is pre-wet into the asphaltcomposition under heating and mixing to 163° C. (325° F.). Once mixtureis pre-wet, material is circulated through a high speed mill until allpolymer has been dispersed into the asphalt cement and no particulateexists. After milling to a smooth and homogeneous dispersion, 3 parts byweight is added of a 325 hydrofinished solvent neutral oil. (The solventneutral oil more preferably could have been added before the polymer toaid in dispersion.) This mixture is then mixed until homogeneous andstored at 149-163° C. (300-325° F.) until it is pumped from storage foruse at the hot mix asphalt plant. Compositions produced according toExample 1 will meet Superpave performance graded asphalt cementrequirements of PG 58-34. Actual grading of this composition at thespecification limits are PG 58.5-35.6.

EXAMPLE 2

To a conventional mixing kettle equipped with agitators and circulationto a high speed mill are added 88 parts by weight of AC5 asphalt cementmanufactured to meet specification limits of AASHTO Table 2 forViscosity Graded Asphalt Cements, 6 parts by weight of a linear styrenebutadiene styrene triblock polymer manufactured by Shell ChemicalCompany under the trade name Kraton D-1101. Polymer is pre-wet intoasphalt cement under agitation and heating until reaching a temperatureof 163° C. (325° F.). Once mixture is pre-wet and temperature isreached, mixture is circulated through a high shear mill until polymeris completely dispersed into the asphalt cement and no particulateexists. After milling to a smooth and homogeneous dispersion, 6 parts byweight of a 325 aromatic extract obtained from the furfural treatmentprocess of lubricating oils are added. This mixture is agitated untilhomogeneous and stored at 149-163° C. (300-325° F.) until the materialis pumped from storage for use at the hot mix plant. Compositionsmanufactured according to Example 2 have been found to meet Superpaveperformance asphalt binder grade (Performance Grade) PG 58-28 withactual specification limits met at PG 62.8-33.9 temperatures.

EXAMPLE 3 (Comparative PG 70-22 Blown AC)

An asphalt composition produced from vacuum distillation of crude oilsmeeting conventional Table 2 Viscosity Graded Asphalt Cementspecifications for AC20 is oxidized at 250° C. (482° F.) until asoftening point of 57° C. (135° F.) measured by ring and ball isreached. This material is found to meet PG specification grade PG 70-22with actual specification grade limits met at PG 75.5-22.2.

EXAMPLE 4 (PG 70-22 Blown AC and Invention)

An asphalt composition produced according to Example 3 is heated untilmolten and sufficiently fluid to be mixed with 4 parts by weight of 325hydrofinished solvent neutral oil produces a Superpave asphaltcomposition meeting the grade requirements of PG 64-28 with actualspecification limits met at PG 69.8-28.1.

EXAMPLE 5 (PG 70-22 Blown AC and Cylinder Stock Comparative)

An asphalt composition produced according to Example 3 is heated untilmolten and sufficiently fluid to be mixed with 4 parts by weight ofcylinder stock produced from the conventional refining of crude oils.Compositions according to example 5 are found to meet Superpave gradingof PG 70-22 with actual grading of PG 74.7-23.4.

EXAMPLE 6 (85-100 PenAC Control Comparative)

An asphalt composition produced from the conventional refining of crudeoils to produce a penetration graded asphalt cement meeting therequirements for 85-100 penetration asphalt cements. This material isfound to meet the requirements of Superpave performance specificationgrade of PG 64-22 with actual grading of PG 64.7-26.5.

EXAMPLE 7 (85-100 PenAC Plus Flux as Comparative)

An asphalt composition produced according to Example 6 is mixed with 50parts by weight of a flux material meeting a PG 40-34 produced from thevacuum distillation of crude oils and mixed until homogeneous. Thismixture is found to meet Superpave performance binder specificationrequirements for a PG 52-28 with actual specification limits met at PG54.7-30.6.

EXAMPLE 8 (85-100 PenAC Plus Invention)

A composition according to the invention comprising an asphaltcomposition produced as described in Example 6 is mixed with 4 parts byweight of a 325 hydrofinished solvent neutral oil mixing untilcomposition is homogeneous at temperatures sufficiently high enough tomaintain the materials in a fluid state. Mixtures produced according tothis composition are found to meet Superpave performance binderspecification grading requirements for PG 58-28. Actual specificationlimits are found to be met at PG 59.6-31.0.

EXAMPLE 9 (Invention--Using Preferred Dewaxed oil)

A composition according to the invention comprising an asphaltcomposition conforming to the requirements of a viscosity graded AC5 ismixed with 3 parts by weight of 325 hydrofinished solvent neutral oilmixing until homogeneous further mixing under high shear with 3 parts byweight of a linear triblock copolymer sold under the brand name,Enichem® 6302 at temperatures high enough to maintain the materials in afluid state. Mixtures produced according to this composition are foundto meet Superpave performance binder specification grading requirementsfor PG 58-28 with actual grading of PG 62.5-32.0.

EXAMPLE 10 (Comparative--Using Aromatic Extract)

An asphalt composition produced from vacuum distillation of crude oilsmeeting conventional Table 2 Viscosity Graded Asphalt Cementspecification for AC5 is heated until molten and sufficiently fluid ismixes with three parts by weight of a 325 aromatic extract and mixeduntil homogeneous and further mixing under high shear with three partsby weight of a linear triblock copolymer sold under the brand name,Enichem® 6302 at temperatures sufficiently high enough to maintain thematerials in a fluid state. Mixtures produced according to thiscomposition are found to meet Superpave performance binder specificationgrading requirements for PG 58-28 with actual grading found to be PG61.2-31.0.

EXAMPLE 11 (Invention--Example 9 Without Dewaxing the Oil)

An asphalt composition produced from vacuum distillation of crude oilsmeeting conventional Table 2 Viscosity Graded Asphalt Cementspecification for AC5 is heated until molten and sufficiently fluid ismixed with 3 parts by weight of a 325-waxy distillate until homogeneousand further combined with 3 parts by weight of a linear triblockcopolymer sold under the brand name, Enichem® 6302 at temperaturessufficiently high enough to maintain the materials in a fluid state.Mixtures produced according to this composition are found to meetSuperpave performance graded binder specifications requirements for PG58-28. Its actual grading results are found to be PG 60.3-28.8.

EXAMPLES 12-21

When various formulations are produced and tested according to thetechniques of Example 1 but using the parameters set forth in Table 1,the results are as described in Table 1.

MODIFICATIONS

Specific compositions, methods, or embodiments discussed are intended tobe only illustrative of the invention disclosed by this specification.Variation on these compositions, methods, or embodiments are readilyapparent to a person of skill in the art based upon the teachings ofthis specification and are therefore intended to be included as part ofthe inventions disclosed herein.

Reference to documents made in the specification is intended to resultin such patents or literature being expressly incorporated herein byreference.

                                      TABLE 1    __________________________________________________________________________                1     2     3     4     5     6     7    __________________________________________________________________________    Reference   LB20128T                      LB20020T                            NB20035T                                  LB20067T                                        LB20071T                                              SP20026T                                                    LB20096T    Invention/Comparative                INV   COMP  COMP  INV   COMP  COMP  COMP    FLUX (>300 PEN AC)                              50    85-100 PEN AC                             100   50    AC5         93.5  88    AC20    135F S.P BLOWN AC       100   96    96    CYLINDER STOCK                      4    AROMATIC EXTRACT  6    325 WAXY DISTILLATE    325 HF NEUTRAL OIL                3     6           4    TEXACO HVGO REREF.    ENPROTEC 180N REREF.    1101 SBS POLYMER                3.5    6302 SBS POLYMER    401 SBS POLYMER    MG20/40 GELLED AC    SHRP GRADE  58-34 58-28 70-22 64-28 70-22 64-22 52-28    ACTUAL PG GRADE                58.5-35.6                      62.8-33.9                            75.5-22.2                                  69.8-28.1                                        74.7-23.4                                              64.7-26.5                                                    54.7-30.6    __________________________________________________________________________                8    9     10    11    12    13    14    __________________________________________________________________________    Reference   LB20099T                     B2289-36-1                           B2289-36-2                                 B2289-36-3                                       B2289-35-2                                             B2289-35-3                                                   B2289-35-4    Invention/Comparative                INV  INV   COMP  COMP  INV   COMP  COMP    FLUX (>300 PEN AC)    85-100 PEN AC                96    AC5              94    94    94    97    97    97    AC20    135F S.P BLOWN AC    CYLINDER STOCK    AROMATIC EXTRACT       3                 3    325 WAXY DISTILLATE          3                 3    325 HF NEUTRAL OIL                4    3                 3    TEXACO HVGO REREF.    ENPROTEC 180N REREF.    1101 SBS POLYMER    6302 SBS POLYMER 3     3     3    401 SBS POLYMER    MG20/40 GELLED AC    SHRP GRADE  58-28                     58-28 58-28 58-28 52-28 52-22 52-28    ACTUAL PG GRADE                59.6-31.0                     62.5-32.0                           61.2-31.0                                 60.3-28.8                                       54.3-32.9                                             55.9-30.6                                                   55.2-31.6    __________________________________________________________________________                15    16    17    18    19    20    21    __________________________________________________________________________    Reference   B2289-35-1                      LB20069T                            LB20070T                                  CP20040T                                        LB20170T                                              LB20069T                                                    LB20068T    Invention/Comparative                COMP  INV   INV   COMP  INV   COMP  INV    FLUX (>300 PEN AC)    85-100 PEN AC    AC5         100    AC20                                      96    92    135F S.P BLOWN AC 96    96    CYLINDER STOCK    AROMATIC EXTRACT    325 WAXY DISTILLATE    325 HF NEUTRAL OIL                  3           4    TEXACO HVGO REREF.                      4    ENPROTEC 180N REREF.    4    1101 SBS POLYMER    6302 SBS POLYMER    401 SBS POLYMER                           4     4    MG20/40 GELLED AC             100   97    SHRP GRADE  52-22 64-28 64-22 64-22 64-28 70-22 70-28    ACTUAL PG GRADE                57.1-22.9                      69.1-28.0                            69.4-27.6                                  65.5-25.7                                        64.3-29.0                                              75.9-24.8                                                    70.7-30.2    __________________________________________________________________________

                                      TABLE 2    __________________________________________________________________________    ASPHALT MODIFICATION AGENTS                                        TEXACO        325 HF              100 HF                    325 AROMATIC                            ENPROTECT                                   TEXACO                                        93010 AE    % OFF        NEUTRAL              NEUTRAL                    EXTRACT 180N   HVGO BTMS    __________________________________________________________________________    IBP 653   607   647     450    494  474     1% 682   629   670     554    564  577     5% 749   668   737     690    667  718    10% 782   687   771     724    698  757    15% 802   700   792     744    716  783    20% 817   710   807     760    730  803    25% 829   721   819     774    743  820    30% 840   730   830     786    755  836    35% 850   739   840     797    766  851    40% 859   748   850     808    776  864    45% 868   757   859     818    787  878    50% 877   766   868     829    797  891    55% 885   776   877     840    807  904    60% 894   785   886     851    818  917    65% 902   796   895     862    829  930    70% 911   807   905     875    842  943    75% 921   819   915     888    855  958    80% 931   833   925     901    871  974    85% 942   850   937     916    889  990    90% 955   873   952     934    912  1015    95% 974   907   973     959    946  1063    FBP 1028  986   1033    1015   1030 1151    __________________________________________________________________________

What is claimed is:
 1. A paving asphalt composition comprising pavingasphalt, about 0.1-20 wt. % mineral lubricating oil base stock, andpolymer.
 2. A composition of claim 1 comprising about 0.5-15 wt. %mineral lubricating oil base stock.
 3. A composition of claim 1 whereinthe mineral lubricating oil base stock is substantially free of wax. 4.An asphalt composition of claim 1 additionally containing a gellant. 5.A composition of claim 4 wherein the gellant comprises metallic soapsformed by the neutralization of fatty acids and/or rosin acids;organoclays, e.g., bentonites, kaolin clays, etc.; hydrogenated castoroils; oligomers; siloxanes.
 6. An asphalt composition of claim 1containing an antioxidant.
 7. A composition of claim 6 wherein theantioxidant comprises butylated phenol and/or a metal hydrocarbyldithiophosphate.
 8. A composition according to claim 1, additionallycomprising about 0.1-2.0 wt. % hydrocarbyl dithiophosphate.
 9. Acomposition according to claim 1, additionally comprising about 0.1-5.0wt. % of antioxidant butylated phenols.
 10. A composition according toclaim 1, additionally comprising about 0.1 to 12 wt. % Styrene Butadiene(SB), diblock polymers, Styrene-Butadiene-Styrene (SBS), triblockpolymers which may be either linear or radial, styrene-isoprene-styrene(SIS), diblocked polymers, hydrotreated SBS, Styrene Ethylene ButadieneStyrene polymers (SEBS), Styrene Butadiene Rubber (SBR), polyacrylamide,crumb rubber, and/or glycidyl-containing ethylene terpolymer.
 11. Acomposition according to claim 1, additionally comprising mineralspirits, kerosenes, and/or fuel oil.
 12. A composition according toclaim 1, additionally comprising anionic, cationic or nonanionicemulsifiers.
 13. A paving asphalt composition consisting essentially ofpaving asphalt, mineral lubricating oil base stock and polymer.
 14. Acomposition of claim 13 wherein the mineral lubricating oil base stockcomprises solvent refined paraffinic neutral oil.
 15. A pavementcomposition comprising aggregate and from about 1.0% to about 10.0% of apaving asphalt composition containing from about 1-10 wt. % of a lowtemperature stiffness-reducing amount of mineral lubricating oil basestock.
 16. The composition of claim 15 wherein the mineral lubricatingoil base stock comprises solvent refined paraffinic neutral oil.
 17. Apaving asphalt composition comprising a polymer additive reducing amountof mineral lubricating oil base stock wherein the amount of polymeradditive required to obtain high temperature rutting resistance is lessthan if a similar amount of aromatic extract were added in place of themineral lubricating oil base stock.
 18. A composition of claim 17comprising asphalt blended with from about 0.5-15 wt. % minerallubricating oil base stock.
 19. A process for improving the lowtemperature performance properties of a paving asphalt compositioncomprising blending with said asphalt composition, at a temperaturesufficient to liquefy said paving asphalt composition, a low temperaturestiffness reducing amount of mineral lubricating oil base stock.
 20. Theprocess of claim 19 conducted substantially as a batch process.
 21. Theprocess of claim 19 conducted substantially as a continuous process. 22.The process of claim 19 wherein said blending is a temperature ofsubstantially about 35-205° C. (100-400° F.).
 23. A process according toclaim 19 in which the following ingredients are added in the followingorder: asphalt, mineral lubricating oil base stock, and then polymers.24. A process according to claim 19, wherein the mineral lubricating oilbase stock comprises waste oils, solvent neutral oils, or rerefinedmineral lubricating oil base stocks.
 25. A process for improving the lowtemperature performance properties of a paving asphalt compositioncomprising blending with said asphalt composition, at a temperaturesufficient to liquefy said asphalt composition, from about 0.1 to about20 wt. % of a mineral lubricating oil base stock.
 26. The process ofclaim 25 wherein the mineral lubricating oil base stock comprisessolvent refined neutral oil.